Mixed-delay-dependent L₂-L_? Filtering Technology For Neutral Delay Systems

Time-delay phenomenon inevitably exists in practical systems,especially in industrial systems.The performance of the controlled system affected by time-delay will decrease or even be unstable.Therefore,the influence of time-delay must be considered when studying system stability and controller design.Neutral time-delay systems,as a special form of time-delay system,are always existent in many fields,such as economy,physics,and industrial systems.In view of the truth that the impacts of noise on the systems can be restrained by the L₂-L_?filter,it has attracted considerable attention and many elegant results have been reported.However,as far as the studies of L₂-L_?filters for neutral time-delay systems are concerned,on one hand,the existing conditions did not only consider the effects of constant time-delay,but also did not consider their interrelationship,which have certain limitations.On the other hand,data is transmitted in continuous time or time-triggered mode in most researches,in which mode control system communication bandwidth and resources will be wasted by excessive data transmission.Motivated by above discussions,in this work,we make some efforts to study the mixed-delay-dependent L₂-L_?filter design for neutral time-delay systems on the basis of designing the state feedback controller with suitable gain to make the closed loop system stable,which has theoretical significance and application prospects,and propose an improved event-triggered scheme to reduce the transmission of data effectively.The main contents and achievements are listed as follows:Firstly,the L₂-L_? filtering is designed for a neutral stochastic system with constant time-delay.Before that,state feedback controller with suitable gain is designed to stabilize the closed loop system.By constructing the Lyapunov functional with mixed-delay-dependence and utilizing some novel inte-gral inequality,a less conservative condition can be established.Furthermore,we can obtain the gain matrix of the filter with the aid of matrix transformation and variable substitution.The conditions pro-posed are not only easily checked but also largely applicable.Secondly,the L₂-L_? filtering is designed for a neutral stochastic system with time-varying de-lays.An improved Lyapunov functional with mixed-delay-dependence and novel integral inequalities are utilized to obtain a L₂-L_? filter design of neutral stochastic system with time-varying delays in the form of linear matrix inequalities.This scheme can effectively reduce the conservativeness of the condition especially when the upper bounds of time-delay are different.Thirdly,the L₂-L_? filtering is designed for a neutral system with time-varying delays.Before that,state feedback controller with suitable gain is designed to stabilize the closed loop system.A tra-ditional event-triggered scheme is designed to reduce unnecessary waste of resources in the system.By constructing the Lyapunov functional with mixed-delay-dependence and utilizing some techniques on delay-dependence to obtain the event-triggered scheme and L₂-L_?filter.Finally,based on the traditional event-triggered scheme,a new type of adaptive event-triggered scheme is proposed.The event-triggered threshold of this scheme is not only time-varying,but also can fully reflect the changes of the controlled system in real time.According to the neutral system,a Lya-punov functional with adaptive event-triggered threshold and mixed-delay-dependence is constructed to analyze the stability and designL₂-L_?filter.Compared with the traditional event-triggered scheme,the adaptive one proposed in this paper does not only improves the efficiency of data transmis-sion,but also increases the scope of application of the conditions.